Biomedical subjects

M T Ercan

Publications and source records attributed to M T Ercan.

At least 19 recordsLinked to original sources

PubMed2002

Detection of inflammatory lymph nodes in rabbits by 99mTc-HIG lymphoscintigraphy.

Tc-Human immunoglobulin G ( Tc-HIG) is a well-known radiopharmaceutical for the evaluation of inflammatory lesions. Recently, it has been demonstrated as a new agent for the visualization of the lymphatic system by our group. Our aim was to investigate the feasibility of detection of inflammatory lymph nodes by Tc-HIG lymphoscintigraphy. Ten adult New Zealand rabbits were used as group A. In a baseline study, 37 MBq Tc-HIG (0.1 ml) was injected into both hind legs of the rabbits, and sequential posterior gamma imaging with the rabbits lying prone was performed at 5, 15, 30, 60, 90 and 120 min using a single-headed gamma camera (Toshiba GCA G01 E). One week later, microorganisms ( ) were injected in a volume of 0.1 ml intradermally into the web space between the second and third toes in the bilateral hind legs of each rabbit in order to obtain inflammation in the popliteal lymph nodes. After 4 days, 37 MBq Tc-HIG (0.1 ml) was injected into the hind legs of the rabbits bilaterally, and sequential posterior gamma imaging was performed as described above (second study). Another group of 10 adult New Zealand rabbits (group B) was injected with the same microorganisms in the right hind legs only. After 4 days, scintigraphic imaging was carried out in the same way as described above (third study). Regions of interest were drawn over the injection sites and popliteal lymph nodes on each image for semiquantitative analysis. Count rates for each were calculated and a decay correction was applied. Time-activity curves were generated to show the percentage retention of radioactivity in each region. After the scintigraphic study, some of the group B rabbits were killed by intravenous injection of pentobarbitone (100-150 mg.kg, and both left and right lymph nodes were removed for microscopic examination. On the scintigrams, lymphatic channels and popliteal lymph nodes were visualized within 15 min. In the second study, bilateral popliteal lymph nodes were visualized more clearly than in the baseline study. The right popliteal lymph nodes of the rabbits were more clearly visualized in the third study. Semiquantitative analysis showed a higher percentage uptake of radioactivity in the right compared to the left popliteal lymph nodes in group B rabbits. Microscopic examination of the tissue sections demonstrated inflammation in the right lymph nodes of group B rabbits. In this preliminary study, it was found that Tc-HIG is a new promising agent for the demonstration and evaluation of inflammatory lymph nodes.

Animals↗

PubMed2001

Detection of head and neck cancer with 99Tc(m) glutathione: a correlative study with tissue glutathione and glutathione S-transferase levels.

In this study glutathione (GSH), a natural tripeptide which plays an important role in detoxification reactions, protecting cells against damage from xenobiotics, has been labelled with 99Tc(m) for the demonstration of head and neck cancer. Twenty-eight patients (10 females and 18 males) with various malignancies of the head and neck were given 740 MBq of 99Tc(m)-GSH intravenously and single-photon emission computed tomography (SPECT) images were obtained at 3 h. Semiquantification was performed by drawing regions of interest on three consecutive transaxial slices and tumour to background ratios were calculated. In addition, GSH and glutathione S-transferase (GST) levels were measured in the tumour samples and in normal tissue which were obtained during surgery. Scintigraphic images showed that there was increased uptake in the tumour compared to the normal contralateral side (tumour/normal tissue (mean +/- SD) = 1.94 +/- 0.76). The tissue analyses revealed increased levels of GST in tumour tissues, but both GST and GSH levels in tumour were not statistically different from those in the normal tissue. We conclude that scintigraphic visualization of head and neck tumours can be attributed to increased demand for GSH in cancer. Protein binding might account for the prolonged retention of 99Tc(m)-GSH in the malignant tissue. Like other peptides, it is accumulated and excreted by the kidneys, which allows clear visualization of the abdomen without interference from gastrointestinal system activity.

Adult↗

PubMed2001

Scintigraphic imaging of uveal melanoma with 99Tcm-glutathione.

A prospective study with a new tumour-seeking agent, 99Tcm-glutathione (GSH), was performed on 17 patients with choroidal melanoma. Planar and SPECT images using 99Tcm-GSH clearly demonstrated melanotic melanoma but failed to show amelonotic melanomas. Following confirmation of our results by concurrent ultrasonography and magnetic resonance imaging or computed tomography, patients were managed by either 125I plaque brachytherapy, diode laser transpupillary thermotherapy or enucleation depending on the site and location. In combination with other diagnostic tests, 99Tcm-GSH scintigraphy may play a role in the detection of uveal melanoma and its possible distant metastases.

Adult↗

PubMed2000

Diclofenac sodium incorporated PLGA (50:50) microspheres: formulation considerations and in vitro/in vivo evaluation.

Recently, considerable interest has been focused on the use of biodegradable polymers for specialized applications such as controlled release of drug formulations; meanwhile, microsphere drug-delivery systems using various kinds of biodegradable polymers have been studied extensively during the past two decades. Poly (lactide-co-glycolide) (PLGA) polymers have been proven to be excellent drug carriers for microparticulate systems due to their advantages, e.g. biocompatibility and regulatory approval. The administration of nonsteroidal anti-inflammatory drugs (NSAIDs) into the intra-articular cavity in patients with chronic inflammatory disease is complicated due to the short duration of effect. In the present study, controlled-release parenteral formulations of diclofenac sodium (DS), a commonly used NSAID, were prepared for intra-articular administration, and evaluated in vitro for particle size, yield, drug loading, surface morphology and release characteristics. For in vivo studies, Technetium-99m labelled polyclonal human immunogammaglobulin (99m Tc-HIG) was used as the radiopharmaceutical to demonstrate arthritic lesions by gamma scintigraphy. Evaluation of arthritic lesions post-therapy in rabbits showed no significant difference in the group treated with PLGA (50:50) (mw 34000) DS microspheres compared to control groups.

Animals↗

PubMed2000

Biodistribution of 99mTc-glutathione in mice with osteosarcoma: effect of gamma irradiation on tumour uptake.

The aim of this study was to determine the efficacy of 99mTc-glutathione (GSH) in scintigraphic demonstration of osteosarcoma tumour in mice and the effect of gamma irradiation of tumour on tumour uptake of 99mTc-GSH. The biodistribution of 99mTc-GSH was studied in 30 Balb C mice 3 weeks after isotransplanting osteosarcoma OTS-64 in their thighs. The mice were injected with 400 microCi of 99mTc-GSH in 0.1 ml through the tail vein. They were equally divided into two groups. In the second group the tumours were subjected to gamma irradiation for 10 min (20 Gy). The mice in both groups were killed at 1, 3 and 6 h. Scintigrams were obtained at each time point. The organs, tumours, some muscle and some blood were removed, weighed and assayed for radioactivity. Tumour, liver and muscle sections were also obtained for gross autoradiographic studies. The tumours were well visualized on scintigrams. The tumour uptake values as a function of time after injection were 3.27+/-0.80, 1.53+/-0.69, and 1.51+/-0.55 for the control and 5.18+/-1.28, 0.399+/-0.120, and 1.67+/-1.05%/g for the irradiated groups at 1, 3 and 6 h, respectively. The tumor-to-muscle concentration ratios were 34.03+/-12.2, 21.4+/-11.3 and 18.7+/-11.4 for the control and 18.8+/-7.2, 3.63+/-1.9, and 24.1+/-9.0 for the irradiated groups, respectively. The gross autoradiographic images of tumour sections indicated focal sites of increased uptake within tumour tissue, indicating the presence of necrotic areas. In conclusion, 99mTc-GSH accumulated in osteosarcoma and resulted in high tumour-to-other tissue concentration ratios in mice. The increase in uptake values after tumour irradiation might be a result of increased demand of tumour cells for GSH attributable to its well-known biological function as a reducing agent in addition to increased blood flow and capillary permeability in malignant tissues.

Animals↗

PubMed2000

Microleakage study of various soft denture liners by autoradiography: effect of accelerated aging.

STATEMENT OF PROBLEM: The longevity of soft denture liners is a major clinical problem. Debonding of the soft liner from the denture base material is one of the factors that influence their longevity. Debonding of the soft liner can be attributed to microleakage at the interface. PURPOSE: This study investigated microleakage at the interface of various soft liners and base materials. MATERIALS AND METHOD: Six soft liners were investigated. Forty specimens of each material in disk form (10 mm in diameter, thickness of approximately 4 mm) were prepared. Twenty specimens of each material were stored in an accelerated weathering tester for 900 hours. For 2 days, all disks were immersed in (45)Ca radioisotope solution, then they were embedded in acrylic resin blocks and sectioned longitudinally. Autoradiographic imaging was used to determine microleakage at the interface of the soft liners and their bases. RESULTS: Significant differences between nonaged materials were found (P<.05).The difference between Molloplast B and Mucopren (silanized) was not significant (P<.05). Differences among aged materials were significant (P>.05). Differences between Mucopren (nonsilanized), Mucopren (silanized), and Ufigel P-Tokuyama were not significant (P<.05). Significantly decreased microleakage characteristics were determined for Molloplast B, Mucopren (nonsilanized) and Ufigel P liners after aging. CONCLUSION: Microleakage of Mucopren and Molloplast B lining materials was the lowest. However, the microleakage of Flexor and Simpa was the highest. The aging process did not significantly affect the microleakage characteristics of the Simpa, Flexor, Mucopren (silanized), or Tokuyama materials. Molloplast B, Mucopren (nonsilanized), and Ufigel P materials should significantly decrease microleakage properties after aging.

Autoradiography↗

PubMed2000

Therapeutic radiopharmaceuticals.

A variety of radiopharmaceuticals have been introduced for the internal therapy of malignant and inflammatory lesions in nuclear medicine. In order to destroy the diseased tissues radionuclides with high linear energy transfer (LET) such as beta, alpha, Auger or low energy conversion electron emitters are needed. The range of beta particles is in mm's so they are effective for large tumors. The range of alpha particles is short, only a few cell diameters. Thus, they are effective in treating circulating malignant cells and micrometastases. The range of Auger and conversion electrons is <0.1 micro m. They are very effective in cell killing when they are carried across cell membrane into the nucleus to damage DNA. Appropriate ions, molecules and particles are labelled with such radionuclides and used as radiopharmaceuticals in many different applications. For an effective dose to be delivered high target to non target ratios must be attained. Monoclonal antibodies to specific antigens expressed on tumor cells have been developed to increase the uptake by malignant tissues by specific accumulation. Radiolabelled peptides such as somatostatin, small molecules such as metaiodo-benzylguanidine (MIBG) and many different nano-and micro-particles have been investigated. The effectiveness of therapy can be increased by direct locoregional administration of the radiopharmaceutical. This way the radiation effects are confined locally and the normal tissues are spared from radiation effects. In this review article selection criteria and characteristics of radionuclides and carrier ions, molecules and particles for various therapeutic applications will be discussed, including mainly the recent developments.

Animals↗

PubMed2000

Radiopharmaceuticals for the visualization of infectious and inflammatory lesions.

Many radiopharmaceuticals have been introduced for the scintigraphic demonstration of infectious and inflammatory lesions and some of them are currently in clinical use. They can be classified into two major categories according to their specificity. Specific radiopharmaceuticals include in vitro labeled leukocytes, radio-labelled monoclonal antibodies, and receptor specific small proteins and peptides. Nonspecific radiopharmaceuticals include radiolabelled nanocolloids, liposomes, macromolecules such as human immunoglobulin, dextran and human serum albumin, various small molecules and ions. In this review article radiopharmaceuticals in their respective groups are discussed as to the efficacy, and other parameters such as the physical characteristics of the radionuclides used, radiochemistry involved, availability, cost and biodistribution, emphasizing recent developments.

Animals↗

PubMed1998

Visualization of orbital retinoblastoma with technetium-99m (V) dimercaptosuccinic acid.

The potential contributions of technetium-99m (V) dimercaptosuccinic acid scintigraphy in the evaluation of orbital retinoblastoma, its local extensions and metastases were assessed in this study. Both planar and SPECT images clearly demonstrated the primary tumor and metastatic sites. Following confirmation of our results by contemporaneous ultrasonography, MRI and a subsequent incisional biopsy, the patient was treated with external beam radiotherapy and chemotherapy. This preliminary study showed that in combination with other diagnostic tests, Tc-99m (V) DMSA scintigraphy may play a role in the detection and follow-up of the local tumor extensions and metastases in patients with retinoblastoma.

Biopsy↗

PubMed1998

Technetium-99m (V) dimercaptosuccinic acid uptake by choroidal melanoma before and after iodine-125 brachytherapy.

PURPOSE: The value of the new tumour-seeking agent technetium-99m (V) dimercaptosuccinic acid (99mTc (V) DMSA), is assessed by the visualization of choroidal melanoma before and after iodine-125 episcleral plaque brachytherapy. METHODS: A prospective study was conducted on 12 consecutive patients with choroidal melanoma that was to be treated with plaque brachytherapy. The pre-operative mean (+/- SD) maximal tumour basal diameter was 12.9+/-2.9 mm and the mean tumour height was 8.2+/-2.9 mm. Each patient had planar scintigraphy and single-photon emission computed tomography using 99mTc (V) DMSA 2 days before treatment and 8 months following plaque removal. The calculated tumour to background ratios of these two tests were compared. RESULTS: The pre-operative tumour to background ratio was 1.8+/-0.4 and all tumours could be correctly identified. At the time of postoperative imaging, all melanomas showed varying degrees of regression. The mean tumour height was 4.4+/-2.1 mm. The tumour to background ratio was 1.4+/-0.3. The difference between the two scintigraphic results was statistically significant (P = 0.002). CONCLUSIONS: Technetium-99m (V) DMSA scintigraphy can accurately detect choroidal melanoma and document tumour response following episcleral radioactive plaque therapy. As such, this test can be an alternative ancillary investigative tool in the rare event of opaque media or diagnostic uncertainty.

Brachytherapy↗

PubMed1998

Evaluation of 99Tcm-HIG as a lymphoscintigraphic agent in rabbits.

In this pilot study, 99Tcm-labelled human immunoglobulin G (99Tcm-HIG) was evaluated as a lymphoscintigraphic agent in five rabbits. It was injected intradermally into the web space of the hind legs of the rabbits (37 MBq/0.1 ml). Sequential scintigrams were obtained using a gamma camera for 120 min. The injection site and the hind legs were massaged post-injection. Blood samples were obtained at 5, 15, 30, 60, 90 and 120 min. Two of the rabbits were killed after 2 h. Their organs were weighed and tissue specimens were obtained, weighed and counted against a standard using a gamma counter. The lymph channels and the lymph nodes were well visualized on the scintigrams. The background activity was very low, making interpretation easier. About 30% of the injected dose migrated from the injection site by 2 h. The mean popliteal lymph node uptake was 5.71 +/- 4.62% per gram of tissue. The lymph node to other tissue concentration ratios were very high, ranging from 63:1 for the kidneys to 1099:1 for the heart. We conclude that 99Tcm-HIG is a promising new agent for the visualization of the lymphatic system due to its easy labelling procedure, the stability of the label, its widespread availability and good image quality. It may potentially be useful in detecting and evaluating inflammatory lymph nodes.

Animals↗

PubMed1997

Scintigraphic visualization of ocular melanoma with Tc-99m glutathione.

In a patient with ocular melanoma scintigraphy obtained with 99mTc-GSH clearly demonstrated the histologically proven ocular lesion both in planar and SPECT images. 99mTc-sestamibi study obtained in the same patient three days later was negative. 99mTc-GSH is a potential alternative to the currently used radiopharmaceuticals for imaging both cutaneous and ocular melanomas and their metastases.

Eye Neoplasms↗

PubMed1997

Visualization of uveal amelanotic melanoma with technetium-99m(V) dimercaptosuccinic acid.

The possibility of using technetium-99m(V) dimercaptosuccinic acid, Tc-99m DMSA, in the evaluation of uveal amelanotic melanoma was assessed in this study. Both planar and SPECT images clearly demonstrated the tumor. Following confirmation of our results by contemporaneous ultrasonography and MRI the patient was treated with Iodine-125 brachytherapy. In combination with other diagnostic tests, Tc-99m(V) DMSA scintigraphy may play a role in the detection of uveal melanoma and its possible systemic metastases.

Adult↗

PubMed1997

Evaluation of 99mTc-citrate, 67Ga-citrate and 99mTc(V) dimercaptosuccinic acid for the scintigraphic visualization of acute appendicitis.

An experimental study was planned to evaluate 99mTc-citrate, 67Ga-citrate and 99mTc(V) dimercaptosuccinic acid (DMSA) as agents for the visualization of acute appendicitis. Appendiceal ligation was performed through a midline incision in 24 rabbits. Twenty-four hours later the animals were divided into three equal groups. The rabbits were injected through the aurical vein with 1 mCi (37 MBq) 99mTc-citrate in group I, 0.5 mCi (18.5 MBq) 67Ga-citrate in group II and 1 mCi (37 MBq) 99mTc(V) DMSA in group III. After 3 h, static images of the rabbits were obtained with a gamma camera. There were positive images in seven, six and five rabbits in groups I, II and III respectively. The image quality was better in group I than in the other groups. Also, the mean uptake in group I was significantly higher than those of other two groups (P < 0.05). There was no significant difference between groups II and III (P > 0.05). All rabbits had appendicitis confirmed histologically. In conclusion, these results show that 99mTc-citrate is preferable to 67Ga-citrate and 99mTc(V) DMSA for the differential diagnosis of acute abdominal inflammations such as appendicitis, because of higher concentration ratios, simple and rapid preparation, low cost, excretion mainly through the kidneys and fast blood clearance.

Acute Disease↗

PubMed1997

Measurement of blood flow by the 133Xe clearance technique to grafts of amnion used in vestibuloplasty.

The purpose of this study was to determine the blood supply to lyophilized amniotic membranes when used as graft material in vestibuloplasties. 133Xe clearance technique was used to measure the blood flow to the grafts. A total of 20 patients had either Clark (10) or Kazanjian (10) vestibuloplasties. The blood flow was determined at 2-3 days preoperatively and at 10 and 30 days postoperatively. The preoperative mandibular anterior alveolar mucosal blood flow was 34.4 +/- 10.7 and 23.1 +/- 13.1 ml/100 g/min for the Clark and Kazanjian groups, respectively. Ten days after vestibuloplasty operation with lyophilized amniotic membrane graft application the blood flow to the graft increased to 56.8 +/- 45.4 and 62.6 +/- 30.4 ml/100 g/min for the Clark and Kazanjian groups, respectively. The corresponding values at 30 days postoperatively were 24.6 +/- 10.2 and 22.2 +/- 9.2 ml/100 g/min, indicating the return to normal levels. The changes in blood flow as a function of time were statistically significant in each group (P<0.05). Our results demonstrated the angiogenic effect of lyophilized amniotic membranes until mucoid degeneration after 10-15 days.

Adult↗

PubMed1997

Autoradiographic determination of marginal leakage of a pressed glass ceramic inlay.

The marginal integrity and microleakage of pressed glass ceramic inlays were evaluated using autoradiography. IPS/Empress ceramic inlays were fabricated for 10 human molar mandibular teeth. After adjusting the inlays, they were etched with 37% phosphoric acid gel for 30 s and silanized with Monobond S for 30 s. Before cementation with dual cure resin cement the inlays and cavity walls were gently covered with a thin layer of bonding agent. When the cementation process was completed the samples were cycled 300 times between a 55 degrees C hot bath and a 5 degrees C cold bath. The samples were placed in each bath for 60 s, with 5 s intervals between immersions, then the specimens were immersed in an aqueous solution of Ca-45. After 24 h the inlay and tooth assemblies were removed, rinsed with water and placed in cold-cured acrylic resin, then sectioned through the long axis for autoradiographic analysis. According to the penetration of Ca-45, the microleakage level was scored for each section. The results indicated slight penetration of Ca-45 on autoradiographic films.

Acid Etching, Dental↗

PubMed1997

Accumulation of 99mTc-Cysteine in experimental inflammatory lesions in comparison to 99mTc-glutamine and 99mTc-HIG.

AIM: The aim of this experimental work was to investigate the efficacy of 99mTc-L-Cysteine (Cys) in scintigraphic visualization of inflammatory lesions in comparison to 99mTc-L-glutamine (G), and 99mTc-HIG. METHODS: In mice abscesses were induced by intramuscular injection of turpentine. Six days later mice were injected with 3.7 MBq of each agent and sacrificed in groups of three at 1, 3, 6 and 24 h. Scintigrams were obtained with a gamma camera. The organs, some blood, abscesses, some muscle and urine were removed, weighed and counted in a gamma counter. Percentage of uptake by organs and per gram tissues and abscess/normal tissue concentration ratios were calculated. Experimental arthritis was produced in 6 New Zealand rabbits by intraarticular injection of ovalbumin. Four days later 37 MBq of 99mTc-Cys and 99mTc-HIG were each i.v. administered to 3 rabbits. Scintigrams obtained at 1, 3, 6, and 24 h demonstrated the arthritic joints very well. ROI's over arthritic joints were compared to contralateral normal joints (A/C). RESULTS: In mice the abscesses were well visualized on all scintigrams. The maximum abscess/muscle ratios were 5.21 +/- 1.09 (6 h), 3.73 +/- 0.81 (3 h) and 5.98 +/- 1.17 (24 h) and the maximum abscess/blood ratios were 3.46 +/- 1.33 (24 h), 1.81 +/- 0.10 (6 h) and 0.914 +/- 0.351 (24 h) for 99mTc-Cys, 99mTc-G, and 99mTc-HIG, respectively. In rabbits the maximum A/C ratios were 2.61 +/- 0.53 (3 h) and 2.92 +/- 0.99 (24 h) for 99mTc-Cys and 99mTc-HIG, respectively. CONCLUSION: Our results indicate that 99mTc-Cys is a promising agent for imaging inflammatory lesions. It is preferred to 99mTc-HIG, because of higher concentration ratios attained earlier, lower blood background, lower cost and a simpler in-house preparation method.

Animals↗

PubMed1996

Evaluation of Tc-99m(V) DMSA for imaging inflammatory lesions: an experimental study.

The present study evaluated 99mTc(V) DMSA as an agent for the visualization of inflammatory lesions in comparison to 99mTc(III) DMSA and 99mTC-HIG. All three radiopharmaceuticals were prepared with commercial kits. 99mTc(V) DMSA was prepared at neutral pH by the addition of first bicarbonate and then pertechnetate to the kit contents. The labeling efficiency was 99% as determined by ITLC. Abscesses were induced by i.m. injection of 50 microliters turpentine into the right thighs of 36 Swiss albino mice. Six days later 3.7 MBq of each radiopharmaceutical was i.v. administered to 12 mice. The mice were sacrificed at 1, 3, 6 and 24 h later. Scintigrams were obtained with a gamma camera. The abscesses were better visualized on scintigrams with 99mTc(V) DMSA compared to 99mTc(III) DMSA, starting at 1 h. The animals were dissected and the organs were removed, weighed and the radioactivity determined with a gamma counter. The abscess to other tissue ratios were higher with 99mTc(V) DMSA than the other radiopharmaceuticals. The max. abscess/muscle ratios were 9.46 +/- 3.20 (24 h), 4.19 +/- 1.39 (6 h) and 5.98 +/- 1.17 (24 h) and max. abscess/blood ratios were 6.22 +/- 1.41, 4.09 +/- 0.84 and 0.914 +/- 0.351 all at 24 h for 99mTc(V) DMSA, 99mTc(III) DMSA and 99mTc-HIG, respectively. Experimental arthritis was produced in New Zealand white rabbits by intra-articular injection of ovalbumin. Four days later 37 MBq of 99mTc(V) DMSA and 99mTc-HIG were each i.v. administered to 3 rabbits. Scintigrams obtained at 1, 3, 6, and 24 h clearly demonstrated arthritic joints. ROI's over arthritic joints were compared to contralateral normal joints (A/C). The max. A/C ratios were 2.10 +/- 0.31 (3 h) and 2.92 +/- 0.99 (24 h) for 99mTc(V) DMSA and 99mTc-HIG, respectively. Our results indicated the feasibility of imaging inflammatory lesions with 99mTc(V) DMSA.

Abscess↗